Assessing the Contribution of the Oscillatory Potentials to the Genesis of the Photopic ERG with the Discrete Wavelet Transform

Abstract EN

The electroretinogram (ERG) is composed of slow (i.e., a-, b-waves) and fast (i.e., oscillatory potentials: OPs) components.

OPs have been shown to be preferably affected in some diseases (such as diabetic retinopathy), while the a- and b-waves remain relatively intact.

The purpose of this study was to determine the contribution of OPs to the building of the ERG and to examine whether a signal mostly composed of OPs could also exist.

DWT analyses were performed on photopic ERGs (flash intensities: −2.23 to 2.64 log cd·s·m−2 in 21 steps) obtained from normal subjects ( n = 40 ) and patients ( n = 21 ) affected with a retinopathy.

In controls, the %OP value (i.e., OPs energy/ERG energy) is stimulus- and amplitude-independent (range: 56.6–61.6%; CV = 6.3%).

In contrast, the %OPs measured from the ERGs of our patients varied significantly more (range: 35.4%–89.2%; p < 0.05 ) depending on the pathology, some presenting with ERGs that are almost solely composed of OPs.

In conclusion, patients may present with a wide range of %OP values.

Findings herein also support the hypothesis that, in certain conditions, the photopic ERG can be mostly composed of high-frequency components.